1. Field of the Invention
The present invention relates to a process for the beneficiation of fly ash in order to produce increased value components therefrom.
2. Description of Related Art
Disposal of fly ash from coal fired electrical power plants and the like has become increasingly a problem. The annual fly ash production in the United States is more than fifty million tons of fly ash. At the present time, about eighty percent of the fly ash produced is disposed as waste. The disposal cost for this waste ranges anywhere from ten dollars a ton to fifty dollars a ton at the present time and is extremely expensive in light of the large quantities disposed by these power plants.
Some of the fly ash by-product is recycled in its raw form for use as fillers for roadway shoulders and asphalt pavement and the like. It is also known that fly ash contains several beneficial products such as unburned carbons, cenospheres, iron rich spheres, iron silicate spheres and other silicates all of which have beneficial uses if proper separation can be obtained to acquire these products in a pure enough form. For instance, the silicate spheres may be used as a pozzolan composition in a cementatious material and the unburned carbons can be easily converted into activated carbon which is a highly profitable by-product of fly ash waste.
In the past, several dry type beneficiation processes have been attempted in order to remove and separate various useable products of the fly ash. However, these processes have generally not allowed adequate separation between the various fractions of the fly ash and therefore the processes and resulting products have not been particularly marketable or cost effective overall.
Wet beneficiation processes have also been attempted in the past, however, these processes have also not been commercially practicable to adequately separate the desired fly ash components.